<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../vue.global.js"></script>
</head>

<body>
    <div id="counter">
        Counter: {{ counter }}
    </div>

    <script>
        const Counter = {
            data() {
                return {
                    counter: 0
                }
            },

            // Counter挂载完毕【回调】
            mounted() {
                setInterval(() => {
                    // this为当前Counter组件实例
                    this.counter++
                }, 1000)
            }
        }

        Vue.createApp(Counter).mount('#counter')
    </script>
</body>

</html>